A scintillator (www.wikipedia.org) is a material that exhibits scintillation—the property of luminescence when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate, (i.e., re-emit the absorbed energy in the form of light). Sometimes, the excited state is metastable, so the relaxation back down from the excited state to lower states is delayed (necessitating anywhere from a few nanoseconds to hours depending on the material): the process then corresponds to either one of two phenomena, depending on the type of transition and hence the wavelength of the emitted optical photon: delayed fluorescence or phosphorescence, also called after-glow.
Various tools such as scanning electron microscopes and electron beam inspection tools include a scintillators and a light guide.
The scintillator and the light guide are made of different materials and when the scintillator is flat the optical coupling between the scintillator to the light guide is problematic and results in losing a substantial amount of light.
There is a growing need to collect the light from a scintillator in an efficient manner.